Cryptograph enciphering and deciphering device



May 10, 19 I G. A. GRAHAM ET AL 1,857,374

CRYP' GRAPH ENCIPHERING AND DECIPHERING DEVICE Filed March 28, 1929 2Sheets-Sheet 2 Patented May 10,1932

umran STATES PATENT OFFICE GEORGE A. GRAHAM, OF WASHINGTON, DISTRICT OFCOLUMBIA, LOUIS M. EVANS, OF

ALEXANDRIA, VIRGINIA, AND WILLIAM F. FRIEDMAN, OF WASHINGTON, DIS- TRICTOF COLUMBIA; CITIZENS NATIONAL BANK AND MARY E. EVANS EXE CUTORS OF SAIDLOUIS EVANS, DECEASED V CBYPTOGRAPE CIIHERING LEGIPHERING DEVICEApplication filed March 28, 1929. ,Serial no 350,713.

(GR-ANTED UNDER THE ACT OF MARQE 3, 1883, AS AMENDED AIPBIL 30, 1928 8700. G. 757) i The invention described herein may be manufactured and usedby or for the Government for governmental purposes, without the paymentto us of any royalty therein.

' ciphering messages automatically. For pur-' An object of thisinvention 1s to provide a cryptograph adapted to be positioned over thekeyboard of any writing, printing, ortelegraphing mechanism employing amanually operated keyboard, and designed to function as a mechanism forenciphering or deposes of brevity, the writing, printing, ortelegraphing mechanism referred to abovewfll hereafter be designatedmerely as a printing mechanism, it being understood that such mechanismmay consist of an ordinary commerclal mechanlcal or electrlcaltypewriter, a printing telegraph apparatus, etc.;

in other words, any apparatus employing a keyboard for purposes ofwriting or transmitting intelligence is intended to be included by thedesignation. In conformit with the latter statement, when, in theescription which follows, the word print or printing is used, it is tobe understood that this action may take place locally, as on an ordinarytypewriter, or at a distance, as in the: case of printing telegraphsystems, or both, as in the case of printlng telegraphs which make bothtransmitter.

a local and a distant record of the transmission. i

A further object of this invention is the provision of the unique meansby which a key of the printing mechanism keyboard ,is selected and isthen struck to cause the print-.

ing of the cipher or deciphered letter.

A further object and novel feature of this invention is the provision ofan indirect con-- trol of the keyboard of a'printing mechanism 'by thejoint action of a plural-unit-code tape transmitter and aplural-unit-code keyboard The many applications of such a device as anautomatic cryptographing machine which can be used, 'for example, withany commercial typewriter, requiring only to be posiprintin mechanismwith which it is associated; igure 2 isa side elevation view of thecryptograph in its relationship to the keyboard of the printing mechamsmwith which it is associated; Figure 3 is a front view of the same; andFigure 4 shows in detail the arrangements for a master contactcontrolling the entire operations of the cryptograph. i

It is believed that an explanation of a schematic representation of our.invention will form the best basis for its understanding, and thereforereference will be made to Figure 1. In this figure A re resents a planview and D a side elevation o a Baudot keyboard transmitter; Brepresents a perforated-ta'pe transmitter; G represents a plan view, andEa side elevation of a Baudot slotted-bar translator; F represents asideelevation of the keyboard of any printing mechanism G, bearing thestandard keyboard.

The Baudot keyboard transmitter is so -well known in the art of printingtelegraphy that no detailed description of it is deemed necessary. It issuflicient to indicate that we make use of a standard six-bartransmitter, the bars 'being designated 0, 1, 2, 3, 4, 5. The bar 0 actsas a universal bar and serves a'function to be described presently. Thefunction. of'bars 1 to 5 is to control the set of contact levers 6, 7,8, 9, 10. These contact levers are normally at the left, but when a,bar, for example 3, is displaced toward the right by depressing a keybar121 of the keyboard transmitter A, the contact lever 8 is moved to theright and closes contact at 16. The five contact levers beingindependent, it is obvious that the contacts controlled by them can beestablished in a permutative manner to correspond to the permutations ofmarkinggand spacing elements of the wellknown audot five-unit code. Theletter A, for example, is represented in this code by the symbol where aindicates a contact with its right hand contact; and' a will indicatethat the transmitter bar has not moved and that the contact lever ismaking contact with its left hand contact. Thus, as we have arranged it,contact of the levers 6, 7, 8, 9, and 10 is made with theirleftcontacts11,13,15, 17, and 19, respectively, when no displacement ofthe bars takes place, and contact of the levers with their right is madewhen the bars are displaced. Therefore, the contacts set up tocorrespond with .the Baudot code for letter A will be as follows:contact lever 6 closing contact 12; contact lever 7 closing contact 14;contact levers 8, 9, and 10 remaining against contacts 15, 17, and 19,respectively. I

Transmitter bar 0, is, as stated, a universal bar, and has as itsfunction the control of contact 36, which, in conjunction with backcontact 37 of a relay 38, controls a magnet 50 that is a part oftranslator O. The circuit and function of magnet 50 willbe explainedlater. Contact 36 is closed on the depression of any keybar.

A master contact 39 of A, under control of a universal bar 46, serves tokeep the entire system in an inoperative condition until any key ofkeyboard transmitter A is depressed. A tooth at the right extremity ofeach bar 0,1, 2, 3, 4, and 5, will move universal bar 46 to the rightand will thus close contact 39 when an one of the bars is displaced tothe right. t is necessary that the sliding bars of the keyboardtransmitter A be locked into the positions they assume on the depressionof a key until all the subsequentmperations and functions have beencompleted. This is accomplished by means well'known' in the art. Alocking bar 48, controlled by armature 49 of magnet 56 is brought upagainst one side or the other of lugs projecting from the underside ofthe transmitter bars, so that a bar that has been displaced to the rightcannot move back into its neutral position, nor can a bar that hasretained its neutral osition be displaced to the right until the 100 'ngbar has been released. The electrical current for locln'ng magnet 56 isas follows: from positive of battery H through conductor" 91, contactlever 83, closed contact 84, conductor 92, closed contact 39, conductor96, winding of magnet 56, conductors 97, 88, and 87, to negative ofbattery H. Spring 98 holds armature 49 in its unactuated position. Theprincipal parts of the keyboard transmitter A have now been described.It may be stated at this point that we simply make use of this keyboardto set up permutations of electrical impulses locally and not totransmit or radiate them to a distant station.

The tape transmitter B is also so well known in the art of printingtelegraph that no detailed description is necessary. uflice it to saythat it has five contact levers 21, 22, 23, 24, and 25, which movebetween five right-hand or marking contacts 27, 29, 31, 33, and 35, andfive left-hand or spacing contacts 26, 28, 30, 32 and 34, under thecontrol of a perforated tape, by means of five finger pins, not shown,which are present under the mitter the right-hand contacts are in ourterminology contacts, the left-hand ones, I contacts, 12, 14,16, 18, and20, respectively,

contacts. Upon the presentation of a hole in the tape over any of thefinger pins the act ofthe pin rising through the hole allows thepertaining contact lever to move to its right hand contact and thereforemakes that contact one that can be designated by the ign. When the pindoes not go through a hole in the tape the contact lever makes contactwith its left-hand contact, and therefore this can be designated by thesign. The tape is perforated to correspond to the permutations of theBaudot code, and

perforations denoting theletter N, whosev code equivalent is bepresented to the pins of B, contact levers 21, 22, and

25 will be against their left-hand contacts 26, 28, and 34,respectively; contact levers 23 and 24 will be against their right-handcontacts 31 and 33, respectively. The principal parts of the tapetransmitter B have now been described. Again, as in the case of thekeyboard transmitter, it may be stated that we simply make use of thistape transmitter to set up permutations of electrical impulses locallyand not to transmit or radiate them to a distant station.

The Baudot translator C is also well known under the control oftheset'of magnets 51,

52, 53, 54, and 55. These magnets are controlled jointly by the sets ofcontacts of the keyboard transmitter A and the tape transmitter B in amanner well known in the art of printing telegraph cryptographs, so thata brief description will suffice. The electrical principle, in brief, isthat the circuit through any of these magnetscan only be completed whenthe controlling contact levers in the tape transmitter and the keyboardtransmitter are in non-homologous positions as regards their left andright contacts. Thus, in Figure 1, consider magnet 51 of C, the circuitof which is controlled by the two contact levers, 6 of A, and 21 ofB.Only one of four possible cases with respect to these contact levers canexist at a given moment:

Case 1.Contact lever 6 makes contact at 11. Contact lever 21 makescontact at- 26.

When this is the case the circuit for magnet 51 is open. Thus, frompositive of battery H through conductor 91, contact lever 83, closedcontact 84, conductor 92, closed contact 39, conductor 99, contact lever6, contact 11, conductor 66 to contact 27 which is open, and hencemagnet 51 cannot be ener 'zed.

Case 2.Contact lever 6 no es contact at 11. Contact lever 21, makescontact at 27 When this is the case the circuit as traced directly aboveremains the same up to the conditionof contact 27 This now being closed,the current can continue through contact lever 21, conductor 100,winding of magnet 51, conductors 105, 106, resistance 60 and relay 38,conductors 107 and 108 to negative of battery H. Magnet 51 is thereforeenergized.

Orwe 3.-Contact-lever 6 makes contact at 12.. Contact lever 21 makescontact at 27.

The circuit as described for the two preceding cases is the same here upto contact lever 6, which now being against contact 12 the currentcontinues along conductor 61 to contact 26, which .is now open. Hencemagnet 51 remains unenergized.

Uase 4.Contact lever 6 makes contact at 12. Contact lever 21 makescontact at 26. The circuit under Case 3 can now be completed, fromcontact 26 through contact lever 21, conductor 100, and thence, ,by pathdescribed under Case 2, to negative ofbattery H. Hence, magnet 51 isenergized.

It is thus seen that when the homologous governing contact levers are insimilar positions no circuit is established through the pertainingmagnet of C; only when one contact lever is at the left or minus signcontact,

and the other homologous contact is at the right or plus sign contactwill the'circuit be completed. It is immaterial which lever is makingthe plus contact, which the minus contact. p

As said before, magnet 51 has four companion magnets, 52, 53, 54, and55, the circuits for which are similar in character to broken, aretractile springat the left extremity. of the bar brings the latterback into'its normal position.

The various permutative positions assumed by the translator bars of C,Figure 1, determine the selection of the letter to be printed by theprinting mechanism over which the cryptograph is positioned. These barsare slotted, the slots being so arranged that, as .the bars aredisplaced to the right under the action of magnets 51 to 55, there willbe for each different permutative arrangement of the translator bars oneand only one alignment of slots presented under the set of stunt bars orselectable members 109, into which a particular bar can drop, beingpulled by a spring attached .to one extremity of. the said bar. (Sideelevation E shows one spring, 122.) The bar selected is not permitted todrop into the alignment of slots until a universal bar 110 of A (110' ofE) is released under the action of a magnet 57 of E, circuit for whichis closed by contact 58. This contact 58is operated by a bar 59 which isdis-' placed to the right when any of the translator bars 41, 42, 43,44, 45, or the extra bar 40 is pulled to the right. The circuitformagnet 57 is as follows: from positive of battery H through conductor91, contact lever 83, closed contact 84, conductor 92.

shaft 114 of C (114 of E) which closes a contact 115 of E. This contactcontrols the printing magnet 73, whose armature 74, which swings aboutan axis 75, actuates the printing drive pin 76. The circuit for magnet73 is as follows: positive of battery K, conductor '118, winding ofmagnet 73, conductor 119, closed contact 115, conductor 120 to negativeof K. In practice batteries K and H are the-same, being here shown asseparate only for the sake of clearness of circuit tracing. Also thebatteries are simply to represent a source of E. M. R; either machine orbattery for the equipment can be designed for a range of voltages. g

When a selectable member drops into position it draws down with it draglink 77 presenting the slot in "member 78 before the printing drive pin76. When magnet 73 is energized, member 78 is driven forward operatingdrive bar 79 by bell crank action about shaft 80. Drive bar 7 9 in turnoperates a plunger 81 which actuates the proper key of keyboard F ofprinting mechanism G. When drive bar 7 9 is practically at the bottom ofits stroke it operates crank 82 thereby moving contact lever 83 fromcontact 84 to contact 85. This action'causes two things to happen: (1)The tape step forward magnet 47 in tape transmitter B is energized, thecircuit being from positive of battery H through conductor 91, contactlever 83, contact 85, conductor 90, Winding of magnet 47, conductors 89,88, and 87, to negative of battery H; (2) when contact 84 is opened theentiresystem restored to normal in the followin manner: circuit for lockmagnet 56 is broken at contact 84, thus releasing the transmitter barsof A and in turn opening master contact 39. Then the latter contactopens, the circuit for universal bar magnet 57 of translator C isbroken, the return of the universal bar 110 of A (110 of E) under actionof spring 71 raising the selected member 109 of G. 'llhereup'on thetranslator bars of C return to normal. Crank contact 115 is opened whenthe selected stunt bar comes out of the slots,'print magnet 73 isdeenergized, armature is retracted by spring 123, and print bar 7'9returns to normal. The latter releases crank'82, contact lever 83 isrestored to make contact at 84, and the entire system is now inreadiness for another operation.

Therenow remains to be explained the function of magnet 50 of C and itsassociated parts and circuit. For the purposes of our invention it isessential that the printing.

mechanism G make some record for each and every depression of thekeybars of the keyboard transmitter A. A consideration of thefunctioning of magnets 51, 52, 53, 54, and 55 will show that when thepermutative .arrangement of the contact levers of keyboard transmitter Ais identical with that of the contact levers of tape transmitter B, noneof the magnets 51, 52, 53, 54, or 55 will be energized. In other words,whenever the Baudot combination set upon A is the same as that set up onB, the resultant is zero, or blank. It is necessary that the printingmechanism make a record of each such case in order that messages may becorrectly deciphered. The details of the method we have devised for isrecording follow.

As already explained, the circuit for magnet 50 is completed only whenkeyboard contact 36 is closed and at the same time the armature 72 ofrelay'38 is at its back contact 37. Contact 36 closes each time any keyof transmitter A is depressed, under action of transmitter bar 0, butcontact 37 is closed only when none of the magnets 51 to 55 isenergized. That is, whenever the resultant of the interaction oftransmitters A and B is anything other than zero or blank, re-

lay 38 is actuated and'contact 37 is broken. That relay 38 will beenergized every time that any .resultant Whatever except blank is set upat magnets 51 to 55 is obvious from the position of relay 38 in thecircuits for those magnets, since in order to reach the negativeterminal of battery H, the current through all these magnets must flowthrough relay 38. The reason for the parallel combination of resistance60 and relay 38 is so that a fairly sensitive relay may be shunted by aresistance of such value that the voltage drop across the combinationwill not be great enough to interfere with the satisfactory op.- crationofmagnets 51 to 55, whether only one operates or whether they alloperate. It is necessary that relay 38 be interposed between battery andmagnets 51 to 55, but it is optional. whether a low resistance relay isused or a high resistance relay shunted by a low resistance unit. When,however, the resultant is blank, then and only then will contact 37remain closed and magnet 50 energized. The circuit for magnet 50 is thenas follows: from positive of battery H through conductor 93, winding ofmagnet 50, conductor 94, closed contact 36, conductor 95, contact lever7 2, contact 37, conductor 87 to negative of battery H. The armature ofmagnet 50 isyoked to the sixth translator bar, 40, which, like the othertranslator bars, is drawn toward the right when magnet 50 is energized.Translator bar 40 determines the selection of a stunt bar which in turncauses the printing of a character. In the position shown as occupied bythe stunt bar referred to, the character printed will be 1 ardtypewriter, but it can, of course, be caused to print another, a dash.for example.

It has. been seen that there is no direct relation betwen the keybarstruck on the keyboard transmitter A and the letter that. is printed onthe printing mechanism G. The relation is only an indirect one and isinfiuenced bythe tape transmitter B, specifically by the particularBaudot combination that happens to be set up at B at a given 'moment. Ifthe perforated tape passing through B consists of perforationsrepresenting an entirely random, unintelligible sequence of letters itobviously becomes an encipherin key which may be employed to transforman intelligihle communication into an unintelligible one that will besecret to all except those possessing the key. Since the tape advancesautomatically after each printing operation, the enciphering key changeswith each letter to be enciphered, and this can be extended indefinitelyby making the perforated tape as long as the text to be enciphered.

It will now be assumed that the keybar for letter A is struck on thekeyboard transmitter A, and that at the same time the finger pins intape transmitter B are set up according to according to the keyboard ofa stand-.

gas

the Baudot code for letter N. From what has been said in connection withmagnets 51 to 55 it will be clear that .the resultant of the interactionof these two letters will be as follows:

Keyboard transmitter g A Tape transmitter Translator The resultantpermutation corresponds to letter K. Translator bars 41, 42, 4:3, and 44will be drawn to the right under the action of energized magnets 51, 52,53, '54, the electrical circuits for which are deemed sufficiently wellunderstood from the foregoing description to warrant'their tracing beingomitted.

The K stunt bar will be the one selected and will drop into the alignedslots on the translator bars upon the energi'zati on of the tact 115 touniversal barmagnet 57 by closing of contact 58. When the K stunt bardrops into posi-- tion drag link 77 draws member 78 down, presenting itsnotch before printing drive pin 76; the K stunt bar also causes crankconbe closed and print magnet 7 3 is energized, causing print bar 7 9 tobe driven down, depressing the K plunger, 81, and causing the printingmechanism G to print the letter K. At the end of the downward stroke ofbar 79, crank 82 opens contact 84 and closes contact 85. The results ofthe operation 0 the crank 82 have already been set forth, the entiresystem being cleared and made ready for the next cycle.

' a case of enciphering,

have been dealing with wherein A is the plaintext letter, N, the keyletter for 'enciphering A, and K the resultant cipher letter, thedecipherment requires thatvthe depression of keyboard K on thetransmitter A, combined with-the settingup of letter N on tapetransoriginal plaintext letter. The interaction may be shownschematically as follows:

Assuming that we Cipher letter K Keyletter-N I :13";

' Plain-text-letter A= V In this case only magnets 51 and 52 would beenergized,,.the A stunt bar or member selected, and A printed on theprinting mechanism G. Thus, the reciprocal relationship between theplain-text and cipher letters through the intermediacy of the key letterN has been maintained.

We may now proceed to a description of the apparatus in its mechanicalaspects. Figure 2 is a side elevation view of the cryptograph in itsrelationship tothe keyboard of the printing mechanism with which it isassociated. The side frame of the cryptograph is shown removed, for thesake of clearness.

, extremities by ball and roller bearings.

bar magnets,

In this figure the portion .denoted by A is the crytograph, and Bdenotes the keys of the printing mechanism. The keybars, 1', of thecryptograph A are pivoted on a common shaft, 2', and are held up byindividual springs, 3. These keybars operate the transmitter bars, 4',which are supported at thTeiilr e mechanism for lockingthetransmitterbars into position is shown as consisting of magnet 5 whosearmature 6, normally held b spring 7 when attracted causes bar 8 to rockon pivot 9' and lock the bars into position. Magnet 10 is one of the setof six translatorthe other five being behind the one shown, eachequipped with an armature, 11 bell crank 12', and coupling 13, formoving the translator bar controlled by it. The translator barsthemselves are shown at 14:. At 15 .is shown but one of the set, ofthirtytwo stunt bars, or selectable members, the

others being behind it. These bars are pivoted at 16' and are pulledinto an alignment of slots on the translator barsl i' under the actionof individual springs, 17. Each select-able member is provided with adrag link,.

bar 22' at pin 23'. Drive bar 22 operates with a bell crank action aboutshaft 24 which is common to all the drive bars. When memf her 19is drawndownward by the action of a translator bar, 15, upon drag link 18, itpresents its slot 21' before the drive pin 25', which is commontoandruns under all the slotted members, of which 19' is but one.

Drive pin 25 magnet 26, whose armature 27', held neutral by the pull ofspring 28, rocks upon pivot 29'. When magnet ture 27' causes 21' andstrike that member 19 which has been presented to the drive pin, causingdrive bar 22' to be driven downward upon plunger 30. Plunger 30' and allother plungers have, common bearings at 31" and are held up in normalposition by springs such as 32 under 26 is energized its arma-- drivepin 25 to engage slot is under the control of print pin 33. When theplungers are driven downward, their feet, 34', strike the appropriatekeys of keyboard B. When drive bar 22' has almost reached the end of itsdownward stroke it operates crank 35, which is crank 82 of Figure 1.This crank is common to and runs underneath all the drive bars, and onlyone of its bearings is shown at 36'. As explained in connection withFigure 1, the function of this crank is to close the circuit for thetape-stepping magnet i7 of Figure 1, as well as to open the circuit ofthe transmit ter-bar locking magnets 56 of-Figure 1, two operationswhich are machine to normal. At 37 of Figure 2 is shown a crankowhichcorresponds to crank 114 of Figure 1, and controls the contact fornecessary to restore the supports 6 and p for the front and backcontacts and at '13 the print magnet 26 of Figure 2, 7 3 of Figure 1. At38' of Figure 2 is shown a crank which corresponds to bar 59 of Figure1, serving to control contact 58, which governs the circuit for thetranslator universal bar,

110 of A, 110' of E, Figure 1. At 39 of Fig- F ure 2 is shown one of theguides for positioning the cryptograph over the keyboard to insureaccuracy in superposition of the plungers of the cryptograph over thekeys of the printing mechanism.

Figure 3 is a front view of the cryptograph, in which the keys of thekeyboard are designated 1". Only one of the set of transmitter bars isshown, this being the foremost one, designated 2". The manner in whichthe transmitter bars control their contacts is shown for this bar,wherein it is noted that the bar is yoked to contact lever 10",operating the latter about axis 8", thereby presenting contact lever 3to either contact 4", when the bar is at its normal position to the leftand held there by spring 9", or to contact 5", when the bar is displacedto the right upon depressing a key which causes this bar to operate.Proper terminals for wiring are arranged for outhe insulating 7 as shownat 14" and 15 for the contact lever by coiled wire 12, it beingunderstood that the contact lever is insulated from the frame at 11".The other five transmitter bars are directly behind the bar 2", eachcontrolling identical contact levers, all of which are mounted on theinsulating supports 6" and 7". Behind this set of contacts is the mastercontact 39 of Figure 1. In Figure 3 only the crank 27" which controlsthis contact can be seen, but this member and its contact are shown indetail in I Figure 4, which will be discussed later. A

shelf, 19", is provided for placing the tape transmitter (B of Figure 1)into position. The tape transmitter is usually in compact form with nineterminals for external electrical connections. At 16'f is shown one ofthe nine spring clips, equally spaced and mounted upon an insulatingblock 17 for soldered electrical connections at 18". The nine terminalsof the tape transmitter fit under the nine spring clips. A dust coverfor the shelf 19" is provided. At 20",'21' 22", 23", 24", and 25" areshown .the six translator-bar magnets which actuate the translator bars,of which only one, 26", is shown. In this figure only the ends of thestunt bars, or selectable members 28"are visible. They are connected todrag links 40 and at 41 are shown the slotted members (21 of Figure 1)at 42 are shown the drive bars.- At 43 is (114 of Figure 1, 37 of Fig-Figure 1) controlling the print magnet 30*, Figure 3 (73 in Figure 1 and26 in Figure 2); pin 31 is provided with bearings 32 'a' distance,

members 41. At v37 is shown the crank corresponding to crank 82 ofFigure 1, 35' of igure 2. Crank 37 also runs across the ma chine andunder all the drive bars 42, the crank being pivoted at common centers38 and 39. .Magnet 44 is magnet 57 of Fi re 1, the function of which hasbeen explalned in connection with the latter figure. At 45 is shown thetransmitting-bar locking mechamsm.

Figure 4 shows the arrangements for the master contact 39 of Figure 1 asassociated with the keyboard transmitter contacts. In Figure 4 thetransmitter bars 0, 1, 2, 3, 4, and 5 are shown in relation to thecontact levers, of which only three, 7, 8, and 9 are seen; contact lever7 makes contact at 10 when the bar 1 is in its normal position and heldsoby spring 6 ,,or at 11 when the bar is displaced to the right. Twoterminals 12 and 13 for soldered connections are shown. The crank l lpivoted at 15",- operatescontact lever 6,-

be of the simpler type'that consists of but five levers which aremanipulated permutatively by the operator in accordance with therequirements of theiBaudot code.

Furthermore, it should be understood that the keyboard over which the orptograph is to be positioned may be that '0 any sortof printingmechanism that employs the standard keyboard, such as mechanical orelectrical typing machines or typewriters, electrical printing telegraphsystems, etc., and whether a this printing mechanism prints locally orat the applicability of our cerned.

We claim: 1. In combination with an independent printing mechanismhaving a keyboard; a cryptograph adapted to. be positioned overinvention is conthe keyboard of said printing mechanism,

said cryptograplh. including atranslator operative as one unit thereof;means for communicating the action of said translator to the keyboard ofsaid printing mechanism,

said'means consisting of a set of selectable members pertaininglto saidtranslator, a set of drag-link members, a set of slotted members, a setof drive bars, a set of plungers, a print magnet, and a printing drivepin operated by said print magnet, said selectable members beingrespectively connected with said drag-link members, said drag-linkmembers being respectively connected to said slotted members, saidslotted members being or both is of no moment so far as respectivelyconnected to said drive bars, said drive bars being respectivelyconnected to said plungers, said plungers hovering, respectively overthe keys of said keyboard, "5 all of said means being arranged,connected,

and associated so that when a selectable member of said translator isselected and said print magnet is actuated, said printing drivepinengages the slotted member connected to the selected member andcauses the drive bar pertaining to said, selected member to actuate theplunger connected to said drive bar so as to strike the key over whichsaid plunger is hovering.

2. In combination with an independent printing mechanism having a keyboard; a cryptograph adaptedto be positioned over the key board of saidprinting mechanism, said cryptograph comprising a plural-unitcode keyboard transmitter having means for establishing a first set ofelectrical conditions corresponding to aplain-message character in aplural-unit-code; a plural-unit-code tape transmitter havin means forestablishing a second set of electrlcal conditions corresponding to akeying character in the same pluralunit-code, said key board transmitterand said tape transmitter being operatively associated to permitinteraction between said first and second sets of electrical conditions;

a pluraLunit-code' translator comprising means controlled permutativelyin said first and second sets of electricalconditions for communicatingthe action of said translator to the key board of said printingmechanism.

3. In combination with an independent printing mechanism having akeyboard; a cryptograph adapted to be positioned over the keyboard ofsaid, printing mechanism, said cryptograph comprising a plural-unitcodekeyboard transmitter having means for establishing a first set ofelectrical conditions corresponding to a plain-message character in aplural-unit-code; a perforated key-tape transmitter havingm'eans forestablishing a second set of electrical conditions corresponding to akeying character in the same plura unit-code, said key-tape transmitterbeing associated with said keyboard transmitter so that said firstandsecond sets of electrical conditions may react upon each other atranslator'having a set of solenoids-and armatures operative therewith;a slidable slotted translator bar operativelyconnected to each armature;said' solenoids being controlled jointly and permutatively by said firstand second sets ofelectrical conditions; a set of selectable membersoperative with said translator bars and responsive to the interaction ofthe specific'set of electrical conditions set up by said keyboardtransmitter for. said plain message character with, the specific set ofelectrical conditions set upbysaid perforated ey-tape transmitter forsaid keying character; a set of plungers for operating the key- Aprinting mechanism having a 0nd set of 7 controlled jointly andfpermutatively by said board of said printing mechanism and means forcommunicating the movement of each of said selectable withers to one ofsaid plungers to operate t e keyboard ofsaid printing'mechanism andtocause said printing mechanism to print a cipher character representinthe encipherment of said plain-message c aracter by said keyingcharacter.

4. In combination with an independent keyboard; a Cryptograph adapted tobe positioned over the keyboard of said printing mechanism, saidcryptograph comprising a plural-unitcode keyboard transmitter havingmeans for establishing a first set of electrical conditionscorresponding to a cipher character in a plural-unit-code; a perforatedkey-tape transmitter having means for establishing a secelectricalconditions correspondingto a ke'ying'characterin the samepluralunit-code, sai key-tape transmitter being associated with saidkeyboard transmitter so that said first and second sets of electricalconditions may react .upon each other; a translator having a set ofsolenoids associated with their respective armatures; a slidable slottedtranslator bar operatively connected to each armature, said solenoidsbeing first and second setsv 0 electrical conditions; a set ofselectable members and tension means for each member, said selectablemembers being operative with said translator bars and responsive to theinteraction of the specific set of electrical conditions set up-by saidkeyboard transmitter for said cipher character with the specific set ofelectrical conditions set up by said perforated key-tape transmitter forsaid keying character; a set of plungers for operating the keyboard of,said printing mechanism and means for communicating the movement of eachof said selectable members to one of said plungers to operate thekeyboard to said printing mechanism, and to cause said printingmechanism to print a plain-message character representing thedecipherment of said cip her char-, acter by said keying character.

In testimony whereof we afiix our signatures. Y GEORGE'A. GRAHAM.

LOUIS M.- EVANS. WILLIAM F. FRIEDMAN.

